bug in ruby 1.8.7 / ruby 1.9.2 preview 1 (wrong rounding)

ruby187_192_bug

$ ruby -v
ruby 1.8.7 (2010-06-23 patchlevel 299) [i686-linux]

$irb
ruby-1.8.7-p299 > a = (125.33 - (125.33/100.0*50.0))
=> 62.665 
ruby-1.8.7-p299 > b = 62.665
=> 62.665 
ruby-1.8.7-p299 > (a*100).round
=> 6266 
ruby-1.8.7-p299 > (b*100).round
=> 6267 

$ ruby -v
ruby 1.9.2dev (2009-07-18 trunk 24186) [i686-linux]

$ irb
ruby-1.9.2-preview1 > a = (125.33 - (125.33/100.0*50.0))
=> 62.66499999999999 # which is obviously wrong as well
ruby-1.9.2-preview1 >  b = 62.665
=> 62.665 
ruby-1.9.2-preview1 > (a*100).round
=> 6266 
ruby-1.9.2-preview1 >  (b*100).round
=> 6267